Rotatable pull tab to break scored tear strip



May 10, 1966 F. J STEC ETAL 3,250,425

ROTATABLE PULL TAB TO BREAK SCORED TEAR STRIP Filed Feb. 17, 1964INVENTORS YREDERWK J. STEC @"JOHN B.N\CHOLSON j Y W I m OREYS UnitedStates Patent York Filed Feb. 17, 1964, Ser. No. 345,434 Claims. (Cl.Mil-54) This invention relates in general to new and useful improvementsin can ends of the easy opening type, and more particularly to a can endhaving means for facilitating the initial rupture of the end panelthereof as the first step in the tearing out of a removable portion ofthe end panel.

The customary easy opening can end presently in use is provided with apull tab which is secured in place by means of a rivet formed integrallywith the removable, portion of the can end. The mounting of a pull tabon such a can end meets with two conflicting requirements. In the firstplace, the pull tab must be so configurated and so mounted whereby itmay be lifted to apply the initial rupturing force ,on the end panel.Secondly, the pull tab must be sufiiciently recessed within the can endso as to not in any way interfere with the handling of the can end andthe can of which it is a part.

It is the customary practice to first form a can end with the pull tabattached thereto after which the can end is secured to a can body in aconventional double seaming operation. Therefore, it is necessary thatthe pull tab be of a size and so positioned whereby it in no wayinterferes with the handling of the can end utilizing normal can closingmechanism and the seaming of the can end to a can body utilizing suchcan closing mechanism. Then after the easy opening can end has beensecured to the can body, the resultant can is transported in an invertedposition with the easy opening can end temporarily forming the bottom ofthe can. The can is so positioned during the filling thereof and duringthe final closing thereof at which time a normal plain can end issecured to the then upper open end of the can. In the interest ofeconomy, it is necessary that the recessing of the end panel of the canend he maintained at a minimum. Therefore, in order to assure that thepull tab does not interfere with the handling of the can end, thesecurement of the can end to a can body, and the handling of the canformed of the can body and the attached can end, it is necessary thatthe pull tab lie as close as possible to the surface of the end panel ofthe can end.

While it is desirable that the pull tab be, for all practical purposes,held in pressure contact with the end panel of an associated can end, itis also necessary that means he provided for facilitating the lifting ofthe pull tab to effect the initial rupture of the can end along thescore line defining the removable portion thereof. Numerous tests havebeen conducted and on an average it has been found that 14 inch poundsof force is required to effect the initial rupture of the end panel of acan end utilized in the packaging of beer. Since the average pull tabhas an effective length of one inch, it will be readily apparent that alifting force of approximately 14 pounds must be exerted on the free endof the pull tab. Since the pull tab is preferably tightly clampedagainst the surface of the end panel, it will be seen that for allpractical purposes one must place his of her fingernail beneath the freeend of the pull tab and exert an upward force of 14 pounds therewith.This is very diflicult for many people to do. Furthermore, since oftentimes the pull tab is provided with a raw edge, if ones fingers slips,during the opening process, a cut finger will result.

In addition to the foregoing, it will be readily apparcut that since thepull tab must be utilized in the tearing of the removable porion of thecan end from the end panel thereof, even after the initial rupture ofthe can end has occured, it is necessary to retain the pull tab in anelevated position to facilitate the effective gripping thereof.

In view of the foregoing, it is the primary object of this invention toprovide a can end of the easy opening type which includes a removableportion having attached thereto a pull tab in a manner whereby limitedpivoting of the pull tab is permitted, the pull tab being normallydisposed tightly against the upper surface of the end panel of the canend and the end panel being provided with a ramp-like projectiongenerally aligned with the axis of the removable portion whereby whenthe pull tab is rotated, it will ride up on the ramp portion without anyother lifting force being directed thereupon and will automaticallyeffect the initial rupture of the end panel along the score linedefining the removable portion.

Another object of this invention is to provide in an easy opening canend of the type including a pull tab mounted for pivotal movement meansfor automatically lifting the pull tab when it is pivoted whereby asufiicient upwardly directed force is applied to the pull tab to effectthe rupture of the can end along a weakening line thereof and at thesame time the pull tab is held in an elevated posit-ion whereby it maybe readily gripped to effect a tearing out operation on a removableportion of the can end to which the pull tab is secured.

Another object of this invention is to provide a novel can end of theeasy opening type which includes a pull tab for facilitating the openingthereof, the can end being so constructed whereby the pull tab isnormally tightly clamped against the upper surface of the end panel ofthe can end and when the pull tab is rotated into alignment with theremovable portion of the can end to which the pull tab is attached, anupward movement of the pull tab is effected and an initial rupture ofthe end panel will occur.

A f-unther object of this invention is to facilitate the opening ofexisting types of easy opening containers by the provision of the endpanel of each can end with a projection of the ramp type wherein when anassociated pull tab is pivoted about a rivet securing the same to aremovable portion of the can end, the pull tab will automatically beelevated and an initial rupture of the can end will occur.

A still further object of this invention is to provide an easy openingcan end of the type which includes a pull tab for facilitating theopening thereof, the can end being so constructed whereby the pull tabmay be readily lifted without applying a lifting force thereto, and thepull tab, after it has been lifted suificiently to eifect an initialrupture of the end panel will be held in an elevated position tofacilitate the gripping thereof in a manner whereby the pull tab maythen be utilized for the tearing of a removable portion of the can endtherefrom.

With the above and other objects in view that will hereinafter appear,the nature of the invention will be more clearly understood by referenceto the following detailed description, the appended claims and theseveral views illustrated in the accompanying drawing:

In the drawing:

FIGURE 1 is a top perspective View of an easy opening can formed inaccordance with this invention and shows the specific details of theeasy opening can end thereof.

FIGURE 2 is a top perspective view similar to FIG- URE 1 and shows thepull tab of the can end rotated to a position wherein initial rupture ofthe end panel of the can end occurs.

FIGURE 3 is an enlarged fragmentary vertical sectional View taken alongthe line 33 of FIGUREZ and shows specifically the details of the can endconstruction for elfectingthe lifting of the pull tab when the pull tabis rotated and the resultant initial rupturing of the end panel.

FIGURE 4 is an enlarged fragmentary transverse vertical sectional viewtaken along the line 44 of FIG- URE 3 and shows specifically therelationship of the pull tab and a projection of the ramp type formed inthe end panel to effect the lifting of the pull tab when the pull tab isrotated.

Referring now to the drawing in detail, it will be seen that there isillustrated a can of the easy open-ing type, the can being generallyreferred to by the numeral 5. The can 5 includes a conventional can body6 to which there has been attached by means of a double seam 7 an easyopening can end which is .generally referred to by the numeral 8.

The can end 8 for the most part is of a conventional construction andincludes an end panel 9. The end panel 9 has a removable portion 10which is defined by a score line 1-1. The removable portion 10 includesa starting part 12 which is provided with an integral rivet 13. Therivet 13 is utilized to secure a pull tab 14 to the starting part 12.

The can end 8 as described above incorporates conventional features andis difiicult to open. In order that the pull tab 14 in no way interfereswith any operation to be performed in either the making of the can 5,the filling of the can 5 or the closing thereof, it is necessary thatthe pull tab 14 be clamped tightly against the upper surface of the endpanel 9. On the other hand, it is necessaryto lift the pull tab 14 inorder to effect an initial rupture of the end panel 9 along the scoreline 11 immediately adjacent the rivet 13. It will be readily apparentthat if the pull tab 14 is tightly clamped against the end panel 9, itwill be extremely difficult to exert a lifting force on the pull tab 14with ones finger. It has been found that in cans of the type illustratedin the drawing, a force of approximately 14 pounds is required to liftthe pull tab 14 and effect an initial rupturing of the end panel 9.Since there is very little available gripping surface, it will bereadily apparent that it is extremely difilcult for most people to liftthe pull tab 14. Furthermore, often times there is relative slippagebetween the pull tab and ones finger and should an exposed raw edge becontacted by ones finger at the time the slippage occurs, then onesfingers are cut. Accordingly, while the above-described pull tabarrangement has been satisfactory to a certain extent, it has manydeficiencies, and has met with numerous objections.

In accordance with this invention, the pull tab 14 is initially disposedat an angle to the axis of the removable p-o'trion 10 with theillustrated angle of FIGURE 1 being approximately 90 degrees to the axisof the removable portion v10. The end panel 9 is then modified to beprovided with an upwardly directed projection 15. The projection 15 hasan arcuate outline with its center being generally the axis of the rivet13. The projection 15, as is best illustrated in FIGURE 4, is providedat the opposite ends thereof with upwardly sloping ramps 16.

It will be readily apparent from the showings of FIG- URES 1, 2 and 4that when the pull tab .14 is rotated from the position shown in FIGURE1 to a position aligned with the removable portion 10, as is shown inFIGURE 2, the pull tab 14 will automatically ride up one the r-amps ldonto the top of the projection 15 to the position shown in FIGURE 4.This will result in a sufiicient upwardly directed force to effectrupture of the end panel 9 along the score line 11 at the starting endof the removable portion 10.

It will also be apparent from FIGURE 3 that after the initial rupture ofthe end panel 9 along the score line 11 occurs, the pull tab 14 remainselevated above the end panel 9 sufiiciently for one to effectively gripthe pull tab and exert therewith a tearing force on the removableportion 1%) to tear. the same from the remainder of the end panel 9along the score line 11. Thus the projection 15 not only permits theinitial rupture of the end panel to be brought about by a mere swingingor pivoting of the pull tab 14, but also greatly facilitates thecomplete tearing out of the removable portion 10.

In the past it has been proposed to utilize the upstanding seam of a canas a camming surface for the'lifting of a pull tab. However, it will bereadily apparent that since the pull tab is pivotally connected at thecenter of the can end, it is impossible to have the pull tab storedwithin the confines of the can end and at the same time be movable to aposition overlying the seam of the can. Secondly, even if such arelationship were possible, it will be readily apparent that it is stillnecessary to initially lift the pull tab to a position where it overliesthe seam. This is undesirable. With the disclosed pull tab and can endarrangement, it is merely necessary for one to push the pull tab 14 withones finger so that it rotates about the axis of the rivet 13 andgradually rides up onto the projection 15. Inasmuch as the edges of thepull tab may be protected by forming the same with a turned hem, itwillbe readily apparent that the pull tab 14 will have no exposedsurfaces which may be engaged by ones fingers during the pivoting of thepull tab. Furthermore, as pointed out above, the pull tab remains in anelevated position after the initial rupture of the end panel 9 so thatthe pull tab 14 may be firmly gripped for the purpose of completing theremoval of the removable portion 10. A further obvious advantage of thecan end and pull tab arrangement is that since the pull tab does nothave to be lifted whatsoever, it may be clamped fiat against the uppersurface of'the end panel 9 and thus there is no problem of the pull tabundesirably engaging the machinery utilized in applying the can end 8 tothe can body 6 or the machinery for handling, filling and closing thecan 5.

Although only a preferred embodiment of the invention has beenspecifically illustrated and described herein, it is to be understoodthat minor modifications may be made in the disclosed can endconstruction within the spirit and scope of the invention, as defined bythe appended claims.

We claim:

1. An easy opening container element having a removable portion definedby a weakening line, said removable portion including a startingportion, a pull tab, a fastener securing said pull tab to said startingportion for effecting the rupture of said container element along saidweakening line and for limit-ed pivotal movement of said pull tab, andsaid container element having a projection disposed radially outwardlyof said weakening line in the path of pivotal movement of said pull taband adapted to be engaged by said pull tab, said projection including aterminal ramp generally opposing said pull tab whereby when said pulltab is pivoted against said projection, said pull tab will ride up saidramp and onto said projection thereby placing a lifting force on saidstarting portion through said fastener sufiicient to effect an initialrupture of the container element.

2. The container construction of claim 1 wherein that portion of saidcontainer element to which said pull tab is secured is generally flatand said pull tab. is clamped tightly thereagainst.

3. The container construction of claim 1 wherein said projection is inaxial alignment with said removable portion.

4. The container construction of claim 1 wherein said projection isarcuate in outline and has the center of said fastener as a center ofcurvature.

5. A container end of the easy opening type comprising an end panel andan upstanding surrounding seam forming portion, said end panel having aremovable por tion defined by a weakening line, said removable portionincluding a starting portion, a pull tab fully seated within saidcontainer end, a fastener securing said pull tab to said startingportion for pivotal movement, said end panel having a projectiondisposed radially outwardly of said weakening line in the path ofpivotal movement of said pull tab, said projection including a terminalramp generally opposing said pull tab whereby when said pull tab ispivoted against said projection said pull tab will ride up said ramp andonto said projection thereby lifting said pull tab and placing a liftingforce on said starting portion through said fastener sufiicient toeffect an initial rupture of said end panel.

6. The container end of claim 5 wherein said pull tab is tightly clampedagainst said end panel by said fastener.

7. The container end of claim 5 wherein said projection is in axialalignment with said removable portion.

8. The container end of claim 5 wherein the distance between the centerof said fastener and all parts of said seam forming portion is greaterthan the distance from the center of said fastener to a remote end ofsaid pull tab whereby said pull tab cannot engage said seam formingportion.

9. The container end of claim 5 wherein said container end is circularand said fastener is centrally positioned.

10. The container end of claim 5 wherein said projection is arcuate inoutline and has the center of said fastener as a center of curvature.

THERON E. CONDON, Primary Examiner. G. T. HALL, Assistant Examiner.

1. AN EASY OPENING CONTAINER ELEMENT HAVING A REMOVABLE PORTION DEFINEDBY A WEAKENING LINE, SAID REMOVABLE PORTION INCLUDING A STARTINGPORTION, A PULL TAB, A FASTENER SECURING SAID PULL TAB TO SAID STARTINGPORTION FOR EFFECTING THE RUPTURE OF SAID CONTAINER ELEMENT ALONG SAIDWEAKENING LINE AND FOR LIMITED PIVOTAL MOVEMENT OF SAID PULL TAB, ANDSAID CONTAINER ELEMENT HAVING A PROJECTION DISPSOED RADIALLY OUTWARDLYOF SAID WEAKENING LINE IN THE PATH OF PIVOTAL MOVEMENT OF SAID PULL TABAND ADAPTED TO BE ENGAGED BY SAID PULL TAB, SAID PROJECTION INCLUDING ATERMINAL RAMP GENERALLY OPPOSING SAID PULL TAB WHEREBY WHEN SAID PULLTAB IS PIVOTED AGAINST SAID PROJECTION, SAID PULL TAB WILL RIDE UP SAIDRAMP AND ONTO SAID PROJECTION THEREBY PLACING A LIFTING FORCE ON SAIDSTARTING PORTION THROUGH SAID FASTENER SUFFICIENT TO EFFECT AN INITIALRUPTURE OF THE CONTAINER ELEMENT.